Stages of sleep – what happens in the body when we sleep?
Part Two
Deep sleep, and sleep phases. We will discuss all of this in as much detail as possible. We’ve already discussed why we sleep and the theories of sleep. But sleep is even more complex than the theories of sleep described above. There is light and deep sleep, times when we dream and times when we don’t. So, scientists have found that there are phases of sleep, which can be divided into several stages. What happens during the stages of sleep and why is it important to experience them all during the night?
Deep sleep – Sleep phases and stages
Sleep consists of four stages of sleep, repeated several times a night, every 70-120 minutes. The first phase of sleep is called REM – rapid eye movement sleep. When the human body moves into REM, the eyes move rapidly behind the closed eyelids and the brain waves work in a similar way to when we wake up, but this is when we dream. The second phase of sleep is non-REM, when there is no eye movement.
The four stages of sleep:
- Stage 1: non-REM sleep. It happens as soon as you start sleeping, when your body relaxes, your brain waves, heart rate and breathing slow down. It takes about 7 minutes.
- Stage 2: Non-REM sleep. It’s like a light sleep, a prelude to deep sleep. The body temperature drops, the heart rate slows further, the muscles relax even more, and the brain waves briefly increase and then slow down again. Sleep is where we spend most of our time.
- Stage 3: Non-REM sleep. This is the beginning of the deep sleep stage, as deep sleep continues into stage 4. In this third stage, the eyes and muscles are completely relaxed and still, and the brain waves slow down even more. At this stage, our body rebuilds its cells. It is this phase that makes us feel rested and invigorated when we wake up.
- Stage 4: REM sleep. This is another stage of deep sleep, but in it our eyes move rapidly from side to side, our brain waves increase, and our heart rate and breathing speed up. This is the dream phase, when we dream while the brain is processing the day’s information, making it very important for our memory and for remembering new information. The fourth stage occurs after we have been asleep for about 90 minutes.
Then the stages repeat again, but in each repeating cycle we spend less and less time in deep sleep and more time in non-REM sleep.
In sleep research, scientists used to think that the REM phase of sleep was the most important for learning and memory, but more recent research shows that the more restful and restorative phases of non-REM sleep are more important for these tasks, and that it is during REM that spatial and contextual memory is enhanced.
Read about sleep:
Why is sleep so important, why do we sleep?
Sleep deprivation, why is it bad for us?
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Article written by the team at ” Magu Space“